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Laterality is defined as the occurrence of each cerebral hemisphere having asymmetric control over the different sides of the body, leading to preferences to use one side of the body over the other for various behaviors. Many types of laterality exist, but handedness is the form that is most predominantly assessed. Handedness in animals is of special interest to laterality researchers, as humans were once thought to be the only species that exhibited lateralized hand preferences. The aim of the current study was to determine if Asian small-clawed otters (Aonyx cinerea) exhibit significant paw preferences in behaviors associated with completing a specific tool-use task. Video data of the otters completing the task was analyzed for specific paw interactions with the tool-use apparatus, and the percentage of correct completion of the task was documented for each otter. Overall, no significant population level paw preference was present. However, individual differences in paw preference and differing trends in handedness on each focal behavior was present.  The results showed that paw preference (or lack thereof) did affect the tool-use task completion for some otters, and for others, the preference did not seem to have an effect. The main implications of this study are that paw preferences in Asian small-clawed otters are present on an individual level when solving a novel tool-use task.

Background Methods Results Conclusion The Impella 5.5® is commonly inserted via the axillary artery (AX) in patients with cardiogenic shock. The right AX has traditionally been preferred to avoid crossing the aortic arch, and a minimum diameter of 7 mm has been recommended to accommodate the device (21 Fr). There is limited data on choice of laterality of access and AX size required, both in terms of technicality of the procedure as well as outcomes.We performed a single‐center retrospective cohort analysis of patients who underwent Impella 5.5® implantation between December 2020 and February 2024 (N = 75). Data including demographics and outcomes were stratified both by diameter (small, <7 mm vs. normal, ≥7 mm) and laterality of access (right vs. left). Adverse events included stroke, limb ischemia, procedural bleeding or infection, and unplanned explant due to complications. Delivery time was defined as time from advancing the first wire to activation of the device.AX approach was attempted in all (N = 74) but one requiring innominate access, with a technical success rate of 95.9% (N = 71/74). The mean age was 58.8 ± 13.3 years, with 81.1% males. The median delivery time was 7.0 (25th, 75th percentiles: 4.0, 11.5) min with a median support duration of 13 (7.7, 24) days. Ten patients (13.5%) had a small AX, with a mean diameter of 6.3 ± 0.5 mm and were more likely to be younger compared to the normal AX group. Fifty‐nine patients (79.7%) had insertion via the right AX. Median delivery time was comparable across all groups (small, 5.4 [3.5, 10.9] vs. normal, 7 [4.0, 12.1] min, p = 0.59) and (right, 10.4 [5.3, 15.2] vs. left, 6 [3.7, 10.4] min, p = 0.35). There was no difference between the rates of stroke, ischemia, bleeding, or infection when comparing by size or laterality. Survival to discharge was 59.5%, with 21.1% mortality on support, all in patients with a normal AX diameter, but with no difference between right versus left.In our study, laterality and a small diameter of AX access did not affect outcomes of Impella 5.5®, with a similar safety profile. [ABSTRACT FROM AUTHOR]

Hedgehog signaling is a highly conserved pathway that plays pivotal roles in morphogenesis, tumorigenesis, osteogenesis, and wound healing. Previous investigations in patients with Gorlin syndrome found low harm avoidance traits, and increased volumes in the cerebrum, cerebellum, and cerebral ventricles, suggesting the association between brain morphology and the constitutive hyperactivation of hedgehog signaling, while the changes of regional brain volumes in upregulated hedgehog signaling pathway remains unclear so far. Herein, we investigated comprehensive brain regional volumes using quantitative structural brain MRI, and identified increased volumes of amygdala, striatum, and pallidum on the global segmentation, and increased volumes of the lateral and medial parts of the central nucleus of the amygdala on the detail segmentation in Ptch heterozygous deletion mice. Our data may enhance comprehension of the association between brain morphogenic changes and hyperactivity in hedgehog signaling. [ABSTRACT FROM AUTHOR]

The Tactual Span assesses tactile working memory (WM) using both hands while applying forward and backward conditions. The study objectives were to validate a one‐hand version of the Tactual Span and to evaluate WM laterality in the tactile modality. Of the 145 participants, 80 performed the Tactual Span with their right hand, and 65 performed it with their left hand. Moreover, all participants performed two span tasks in the visuo‐spatial and auditory modalities, each encompassing forward and backward conditions. Results revealed adequate Cronbach's alpha values for each hand in both conditions of the Tactual Span, along with a positive correlation between forward and backward conditions in each hand. However, overall performance on the Tactual Span was poorer compared to performance on the Auditory and Visuo‐spatial Spans. Furthermore, in the forward condition, there was a correlation between the Auditory Span and the Tactual Span, but only for the right hand. In the backward condition, the Auditory Span correlated with the Tactual Span in both hands. The findings indicate that there is no effect of hand laterality in tactile WM, showing the two hands are related to each other in their WM function. Additionally, the one‐hand version of the Tactual Span is deemed useful for evaluating tactile WM and can therefore be used in empirical and clinical settings for neuropsychological assessment purposes. [ABSTRACT FROM AUTHOR]

Background: Persistent symptoms have been reported in up to 50% of the 27 million people with mild traumatic brain injuries (mTBI) every year. MRI findings are currently limited by low diagnostic and prognostic sensitivities, constraining the value of imaging in the stratification of patients following mTBI. Limbic system structures are promising brain regions in offering prognostic factors for symptom persistence following mTBI. The objective of this study was to associate volume and symmetry of limbic system structures with the presence and persistence of common symptoms in patients with mTBI. Methods: This study focused on 524 adults (aged 18–82), 58% female, with 82% injured in motor vehicle accidents and 28% reporting loss of consciousness (LOC). Magnetic resonance imaging (MRI) data included a sagittal 3D T1-weighted sequence with 1.2 mm slice thickness, with voxel sizes of 0.93 mm × 0.93 mm × 1.2 mm, obtained a median of 156 days after injury. Symptom diagnosis and persistence were collected retrospectively from patient medical records. Intracranial volume-adjusted regional volumes per side utilizing automated volumetric analysis (NeuroQuant®) were used to calculate total volume, laterality index, and side-independent asymmetry. Covariates included age, sex, LOC, and days from injury. Limbic volumetrics did not relate to symptom presentation, except the (-) association between headache presence and thalamus volume (adjusted odds ratio = 0.51, 95% confidence interval = 0.32, 0.85). Headache, balance problems, anxiety, and depression persistence was (-) associated with thalamus volume (hazard ratio (HR) 1.25 to 1.94). Longer persistence of balance problems was associated with (-) lateral orbitofrontal cortex volume (HR = 1.33) and (+) asymmetry of the hippocampus (HR = 0.27). Persistence of cognitive deficits was associated with (+) asymmetry in the caudal anterior cingulate (HR = 0.67). Depression persistence was associated with (+) asymmetry in the isthmus of the cingulate gyrus (HR = 5.39). Persistence of anxiety was associated with (-) volume of the parahippocampal gyrus (HR = 1.67), orbitofrontal cortex (HR > 1.97), and right-biased laterality of the entorhinal cortex (HR = 0.52). Conclusions: Relative volume and asymmetry of the limbic system structures in patients with mTBI are associated with the persistence of symptoms, particularly anxiety. The conclusions of this study are limited by the absence of a reference group with no mTBI. [ABSTRACT FROM AUTHOR]

Thompson et al., 2023 (Generalized models for quantifying laterality using functional transcranial Doppler ultrasound. Human Brain Mapping, 44(1), 35–48) introduced generalised model‐based analysis methods for determining cerebral lateralisation from functional transcranial Doppler ultrasound (fTCD) data which substantially decreased the uncertainty of individual lateralisation estimates across several large adult samples. We aimed to assess the suitability of these methods for increasing precision in lateralisation estimates for child fTCD data. We applied these methods to adult fTCD data to establish the validity of two child‐friendly language and visuospatial tasks. We also applied the methods to fTCD data from 4‐ to 7‐year‐old children. For both samples, the laterality estimates from the complex generalised additive model (GAM) approach correlated strongly with the traditional methods while also decreasing individual standard errors compared to the popular period‐of‐interest averaging method. We recommend future research using fTCD with young children consider using GAMs to reduce the noise in their LI estimates. [ABSTRACT FROM AUTHOR]

Background: Laterality and bilaterality have been reported as prognostic variables in developmental dysplasia of the hip (DDH) outcomes. However, there is little clarity across the literature on the reporting of laterality in developmental dysplasia of the hip (DDH) due to the variability in severity of the condition. It is widely accepted that the left hip is most frequently affected; however, the true incidence of unilateral left, unilateral right and bilateral cases can be hard to quantify and compare across studies. The purpose of this study was to examine laterality accounting for graded severity in a multi-centre, international prospective observational study of infants with hip dysplasia to demonstrate the complexity of this issue. Methods: A multi-centre, prospective hip dysplasia database was analyzed from 2010 to April 2015. Baseline diagnosis was used to classify patients into a graded laterality category accounting for hip status within the DDH spectrum. Results: A total of 496 patients were included in the analysis; 328 were <6 months old at diagnosis and 168 were between 6 and 18 months old. Of these patients, 421 had at least one frankly dislocated hip. Unilateral left hip dislocations were most common, with 223 patients, followed by unilateral right and bilateral dislocations with 106 and 92 respectively. Stratifying these patients based on status of the contralateral hip, 54 unilateral left and 31 unilateral right dislocated patients also had a dysplastic or unstable contralateral hip. There were significantly fewer bilateral patients in the 6 to 18-month group (p = 0.0005). When classifying laterality by affected hip, bilaterality became the predominant finding, comprising 42% of all patients. Conclusions: Findings from this multi-centre prospective study demonstrate the necessity to account for the graded severity in hip status when reporting DDH laterality. To accurately compare laterality across studies, a standardized, comprehensive classification should be established, as contralateral hip status may impact prognosis and treatment outcomes. Level of Evidence: Level II Prognostic Study. [ABSTRACT FROM AUTHOR]

Hand preference is the preferential use of one hand for a single task. Its study provides insight into the neural mechanisms underlying motor skills, perception, and cognitive functions. From a comparative perspective, it also offers a window into evolutionary history, shedding light on whether manual preferences stem from genetics, environmental influences, or a combination of both. However, there is a paucity of information on preferential hand use for several primate taxa. Here we examine hand preference for the first time in mantled howler monkeys (Alouatta palliata) to determine if there is preferential hand use at the individual and population level as well as sex differences in hand use. We followed 17 wild adult individuals for 10 months and used focal animal sampling (506 focal samples) to record hand use in two types of self-directed behaviors, touching (1246 events) and scratching (1115 events). According to the binomial tests, four individuals were right-hand-preferent, two were left-hand-preferent, and 11 were ambilateral during touching, whereas for scratching seven individuals were right-hand-preferent, two were left-hand-preferent, and eight were ambilateral. At the population level, there was ambilaterality in both behaviors. At the individual level, according to the HI index, hand preference in touching and scratching were not associated and did not vary between sexes. These findings concur with previous studies with howler monkeys and other taxa suggesting that population-level hand preference is not a universal trait across primates. [ABSTRACT FROM AUTHOR]

Objectives/Hypothesis: Recurrent laryngeal nerve injury diagnosed as idiopathic or due to short‐term surgery‐related intubation exhibits a higher incidence of left‐sided paralysis. While this is often attributed to nerve length, it is hypothesized there are asymmetric differences in the expression of genes related to neuromuscular function that may impact reinnervation and contribute to this laterality phenomenon. To test this hypothesis, this study analyzes the transcriptome profiles of the intrinsic laryngeal muscles (ILMs), comparing gene expression in the left versus right, with particular attention to genetic pathways associated with neuromuscular function. Study Design: Laboratory experiment. Methods: RNA was extracted from the left and right sides of the rat posterior cricoarytenoid (PCA), lateral thyroarytenoid (LTA), and medial thyroarytenoid (MTA), respectively. After high‐throughput RNA‐Sequencing, 88 samples were organized into 12 datasets according to their age (P15/adult), sex (male/female), and muscle type (PCA/LTA/MTA). A comprehensive bioinformatics analysis was conducted to compare the left‐right ILMs across different conditions. Results: A total of 774 differentially expressed genes were identified across the 12 experimental groups, revealing age, sex, and muscle‐specific differences between the left versus right ILMs. Enrichment analysis of Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways implicated several genes with a left‐right laryngeal muscle asymmetry. These genes are associated with neuronal and muscular physiology, immune/inflammatory response, and hormone control. Conclusion: Bioinformatics analysis confirmed divergent transcriptome profiles between the left‐right ILMs. This preliminary study identifies putative gene targets that will characterize ILM laterality. Level of Evidence: N/A Laryngoscope, 134:3741–3753, 2024 [ABSTRACT FROM AUTHOR]

Perching or standing on one foot is commonly reported in birds but the level of consistency in using one foot over the other has been less-well documented in most species, particularly birds of prey. For birds experiencing colder temperatures, unipedal perching has been attributed to limiting heat loss through unfeathered legs and feet; individuals should spend longer periods of time perched on one foot as temperatures decrease. Using radio tracking, I collected 486 hours of observations on nine overwintering, free-living merlins (Falco columbarius) in Saskatoon, Canada. Five merlins displayed clear preferences to perch on one foot, however the direction of preference was not consistent and four birds were ambidextrous. There was a curvilinear response in the proportion of time spent in unipedal posture versus temperature, with a peak of ∼22% of the time at moderate temperatures (−10 to −19°C), but lower values at warmer and colder temperatures; the main effect of the squared term for temperature was highly influential while individual foot preference had no impact on the use of unipedal perching. Although preferential use of one foot for perching was displayed by some individuals, thermoregulation may not be the primary driver of this behaviour at colder temperatures. [ABSTRACT FROM AUTHOR]

In recent years, the volume of research on laterality has considerably increased. However, there is a gap in understanding its relationship with education because no comprehensive studies have synthesized all existing information on this topic. Therefore, this study aims to conduct a bibliometric analysis of scientific and academic publications from the past decade (2012--2022) on laterality and education. This study uses high-impact search engines, specifically Web of Science, to compile and analyze relevant works in this field. This research employed an ex post facto retrospective design. The study used a subscription-based database provided by the University of Alicante, specifically the Web of Science Core Collection. This database encompasses various fields, including Sciences, Social Sciences, and Arts and Humanities, and includes 254 categories such as Education Research, Pedagogy, Science Disciplines, and Special Education. After applying the search strategy and various filters in the database, the data were screened according to established inclusion and exclusion criteria. The final sample comprised N = 281 documents. Analysis of these results highlights the benefits of laterality for enhancing motor, neuromotor, and psychomotor skills, which are crucial for the holistic development of individuals. Because these aspects align with key educational objectives, it is recommended to implement classroom methodologies that promote laterality-related activities to assess their effectiveness in practice. [ABSTRACT FROM AUTHOR]

Ulnar Neuropathy of the Elbow (UNE) is the second most common entrapment neuropathy. In this study, we aimed to determine the factors that may guide diagnosis and treatment by examining the electrodiagnostic (EDX), demographic data and upper extremity-related disability levels of patients with UNE. Demographic characteristics, symptom duration, EDX data and any other accompanying entrapment neuropathy, and the shortened Disabilities of the Arm, Shoulder, and Hand Injuries Questionnaire (Quick-DASH) scores were noted. The laterality, localization, factors associated with the severity of UNE, and the impact of the presence of Carpal Tunnel Syndrome (CTS) on disability have been studied in detail. 92 arms of 73 patients were included. The mean age of the patients was 47.71±13.99 years. 41 (56.2%) were male and 32 (43.8%) were female. 29 (39.7%) patients had at least one comorbid disease. Of the patients, 30 (41%) had left-sided UNE, 24 (33%) had right-sided UNE and 19 (26%) had bilateral UNE. The median symptom duration was 3 (1-12) months. 28 (38.4%) patients had also CTS. The median Quick-DASH score was 28 (9-80). There was also no significant association between UNE side and age or gender (p=0.439 and p=0.216, respectively). In 62 (67.4%) patients, the site of compression was 2 cm proximal to the medial epicondyle (ME). Symptom duration was statistically significantly longer in the moderate group than in the mild group, and in the severe group than in the mild UNE group (p [Med-Science 2024; 13(3.000): 616-20]

Study Design A retrospective, cross-sectional study was conducted to analyze the implications of asymmetric baseball movements on the incidence of spondylolysis. Purpose This study aimed to evaluate the relationship between asymmetric movements and the laterality of spondylolysis. Overview of Literature Baseball, characterized by its asymmetric throwing and batting, may disproportionately stress one side. Lumbar spondylolysis is a frequent cause of lower back pain in young athletes, particularly those involved in activities with consistent unilateral rotations such as baseball. However, whether a link exists between the laterality in spondylolysis and the dominant throwing/batting side or whether disparities exist between pitchers and fielders remains unclear. Methods The study included 85 players. Participants were divided into two groups: pitchers and fielders. The association between the laterality of spondylolysis and the throwing/batting side in the overall cohort and between the two groups was evaluated. Results Among pitchers, 16 lesions appeared on the throwing side and 32 on the nonthrowing side (p=0.029). For fielders, no notable difference was observed between the two sides (p=0.363). Furthermore, batting preference did not influence the laterality of spondylolysis in either group. Conclusions Adolescent baseball players, particularly pitchers, exhibited a higher incidence of lumbar spondylolysis on the side opposite their throwing arm. The findings of this study highlight the significant effect of asymmetrical sporting activities on the development of spondylolysis, to which pitchers are particularly susceptible.

Background/Objectives: There exists limited data guiding open-door laminoplasty. The objective of this study is to determine if open-door laminoplasty affects radiographic decompression or arm pain outcomes. Methods: Adult patients who underwent unilateral open-door laminoplasty cervical myelopathy were included. The side opened was dependent on surgeon discretion. We recorded preoperative side of symptoms, side of radiographic compression, arm pain scores, and canal diameter. Patients with open-side ipsilateral or contralateral to dominant symptoms or compression were compared to determine any effect on arm pain outcomes or spinal canal diameter. If the symptoms were equal bilaterally, patients were neutral. Results: A total of 167 patients were included, with an average age of 64 ± 11 years and average follow-up time of 64.5 ± 72 weeks. The average preoperative arm pain visual analog score (VAS) was 2.13 ± 2.86, and the average arm VAS after 6 months was 1.52 ± 2.68. For dominant symptoms, the ipsilateral, contralateral, and neutral groups had a significant improvement in arm VAS at >6 months postoperatively. For dominant compression, the ipsilateral and contralateral groups had a significant improvement in both arm VASs and canal diameter at >6 months postoperatively. No differences were seen between groups for either. We observed a significant correlation between size of plate and change in canal diameter; however, no differences were noted for arm pain. Conclusions: Laminoplasty may be effective in addressing radicular arm pain by increasing the spinal canal's diameter and space available for the cord. The laterality of open-door laminoplasty did not affect arm pain improvement or canal expansion. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to ascertain the prevalence of left-handedness (LH) among otolaryngology--head and neck surgery (ORLHN) practitioners, investigate dexterity's impact on LH trainees, and identify common patterns in their training to improve the training experience. Methods: A web-based survey was distributed anonymously via email to members of the Saudi Otorhinolaryngology Society. The survey targeted ORLHN attending consultants, board-certified registrars, and current residents. It consisted of three sections: the first focused on the experience of attending consultants in training LH individuals, the second investigated common maneuvers employed by rhinologists, and the third explored the experiences and impacts reported by LH trainees. Results: The study included 174 participants, and found a 13.2% LH prevalence among them. Rhinologists showed disparities, with 50% advising trainees to stand on the left side of the bed and use their left hand for the scope, whereas the other half asked otherwise. Additionally, 94.4% of the participants had not encountered any courses specifically tailored for LH trainees. Among LH trainees, 57% and 41% reported difficulties in learning and performing side-specific procedures such as functional endoscopic sinus surgery and endoscopic septoplasty, respectively, often attempting to switch to their nondominant hand, and feeling disadvantaged due to their laterality. Conclusions: Left-handedness presents challenges for both LH trainees and their trainers in surgical specialties, particularly in ORLHN, in which specific positioning and instruments are crucial to gain access to the desired surgical field. Despite these challenges, there is insufficient support for LH individuals. We recommend encouraging LH trainees to openly disclose and discuss their left-handedness, provide them with mentors, establish standardized operating room setups and techniques, supply appropriate instruments, and demonstrate flexibility in accommodating their needs. Level of evidence: Level 5. [ABSTRACT FROM AUTHOR]

Hand movements are associated with modulations of neuronal activity across several interconnected cortical areas, including the primary motor cortex (M1) and the dorsal and ventral premotor cortices (PMd and PMv). Local field potentials (LFPs) provide a link between neuronal discharges and synaptic inputs. Our current understanding of how LFPs vary in M1, PMd, and PMv during contralateral and ipsilateral movements is incomplete. To help reveal unique features in the pattern of modulations, we simultaneously recorded LFPs in these areas in two macaque monkeys performing reach and grasp movements with either the right or left hand. The greatest effector-dependent differences were seen in M1, at low (≤13 Hz) and γ frequencies. In premotor areas, differences related to hand use were only present in low frequencies. PMv exhibited the greatest increase in low frequencies during instruction cues and the smallest effector-dependent modulation during movement execution. In PMd, d oscillations were greater during contralateral reach and grasp, and ß activity increased during contralateral grasp. In contrast, ß oscillations decreased in M1 and PMv. These results suggest that while M1 primarily exhibits effector-specific LFP activity, premotor areas compute more effector-independent aspects of the task requirements, particularly during movement preparation for PMv and production for PMd. The generation of precise hand movements likely relies on the combination of complementary information contained in the unique pattern of neural modulations contained in each cortical area. Accordingly, integrating LFPs from premotor areas and M1 could enhance the performance and robustness of brain-machine interfaces. [ABSTRACT FROM AUTHOR]

Determining the laterality of the seizure onset zone is challenging in frontal lobe epilepsy (FLE) due to the rapid propagation of epileptic discharges to the contralateral hemisphere. There is hemispheric lateralization of autonomic control, and heart rate ismodulated by interactions between the sympathetic and parasympathetic nervous systems. Based on this notion, the laterality of seizure foci in FLEmight be determined using heart rate variability (HRV) parameters. We explored preictal markers for differentiating the laterality of seizure foci in FLE using HRV parameters. Twelve patients with FLE (6 right FLE and 6 left FLE) were included in the analyzes. A total of 551 (460 left FLE and 91 right FLE) 1-min epoch electrocardiography data were used for HRV analysis. We found that most HRV parameters differed between the left and right FLE groups. Among the machine learning algorithms applied in this study, the light gradient boostingmachine was the most accurate, with an AUC value of 0.983 and a classification accuracy of 0.961. Our findings suggest that HRV parameter-based laterality determination models can be convenient and effective tools in clinical settings. Considering that heart rate can be easily measured in real time with a wearable device, our proposed method can be applied to a closed-loop device as a real-time monitoring tool for determining the side of stimulation. [ABSTRACT FROM AUTHOR]

The brain's sensory lateralization involves the processing of information from the sensory organs primarily in one hemisphere. This can improve brain efficiency by reducing interference and duplication of neural circuits. For species that rely on successful interaction among family partners, such as geese, lateralization can be advantageous. However, at the group level, one-sided biases in sensory lateralization can make individuals predictable to competitors and predators. We investigated lateral preferences in the positioning of pair mates of Greater white-fronted geese Anser albifrons albifrons. Using GPS-GSM trackers, we monitored individual geese in flight throughout the year. Our findings indicate that geese exhibit individual lateral biases when viewing their mate in flight, but the direction of these biases varies among individuals. We suggest that these patterns of visual lateralization could be an adaptive trait for the species with long-term social monogamy, high levels of interspecies communication and competition, and high levels of predator and hunting pressure. [ABSTRACT FROM AUTHOR]

Despite wide reporting of a right ear (RE) advantage on dichotic listening tasks and a right visual field (RVF) advantage on visual half-field tasks, we know very little about the relationship between these perceptual biases. Previous studies that have investigated perceptual asymmetries for analogous auditory and visual consonant–vowel tasks have indicated a serendipitous finding: a RE advantage and a left visual field (LVF) advantage with poor cross-modal correlations. In this study, we examined the possibility that this LVF advantage for visual processing of consonant–vowel strings may be a consequence of repetition by examining perceptual biases in analogous auditory and visual tasks for both consonant–vowel strings and words. We replicated opposite perceptual biases for consonant–vowel strings (RE and LVF advantages). This did not extend to word stimuli where we found RE and RVF advantages. Furthermore, these perceptual biases did not differ across the three experimental blocks. Thus, we can firmly conclude that this LVF advantage is unique to consonant–vowel strings and is not a consequence of the repetition of a relatively limited number of stimuli. Finally, a test of covariances indicated no cross-modal relationships between laterality indices suggesting that perceptual biases are dissociable within individuals and cluster on mode of presentation. [ABSTRACT FROM AUTHOR]

The use of functional near-infrared spectroscopy (fNIRS) for brain imaging during human movement continues to increase. This technology measures brain activity non-invasively using near-infrared light, is highly portable, and robust to motion artifact. However, the spatial resolution of fNIRS is lower than that of other imaging modalities. It is unclear whether fNIRS has sufficient spatial resolution to differentiate nearby areas of the cortex, such as the leg areas of the motor cortex. Therefore, the purpose of this study was to determine fNIRS' ability to discern laterality of lower body contractions. Activity in the primary motor cortex was recorded in forty participants (mean = 23.4 years, SD = 4.5, female = 23, male = 17) while performing unilateral lower body contractions. Contractions were performed at 30% of maximal force against a handheld dynamometer. These contractions included knee extension, knee flexion, dorsiflexion, and plantar flexion of the left and right legs. fNIRS signals were recorded and stored for offline processing and analysis. Channels of fNIRS data were grouped into regions of interest, with five tolerance conditions ranging from strict to lenient. Four of five tolerance conditions resulted in significant differences in cortical activation between hemispheres. During right leg contractions, the left hemisphere was more active than the right hemisphere. Similarly, during left leg contractions, the right hemisphere was more active than the left hemisphere. These results suggest that fNIRS has sufficient spatial resolution to distinguish laterality of lower body contractions. This makes fNIRS an attractive technology in research and clinical applications in which laterality of brain activity is required during lower body activity. [ABSTRACT FROM AUTHOR]

The dorsal interosseous muscles (DIM) are intrinsic muscles of the hand located dorsally between metacarpal bones, which play a role in finger abduction. Anatomical variations of these muscles in terms of form and length have been well documented, but variations regarding sex and laterality are underexplored. The aim of this study was to investigate the morphology and morphometry of the DIM of the hand regarding sexual dimorphism and laterality. Twenty human cadavers belonging to the white individuals (n = 40 hands) with known sex and laterality were used for this study. DIMs were dissected and observed for morphology. Also, a digital calliper was used to measure the midpoint length of the DIM. The origin and insertion of all the DIM were normal with the left hand having no additional, supernumerary, and absent muscles in each compartment. The variations were only found on the right side and predominant in females: 2 out of 11 (18.18%) hands containing a space with a supernumerary muscle; 1 out of 11 (9.09%) hands having a space with a double muscle; and 1 out of 11 (9.09%) hands having a compartment with a unipennate muscle. In males, 1 out of 9 (11.11%) hands had a compartment with a supernumerary muscle. The mean midpoint length of each muscle in females and males in both hands from the first to the fourth muscle, respectively, was documented. In females on the left: 46.79 ± 3.56; 42.62 ± 3.57; 49.02 ± 4.21; 41.66 ± 2.15 and right: 47.30 ± 2.49; 39.27 ± 4.14; 45.69 ± 4.64; 38.12 ± 4.08. In males, it was on the left: 50.01 ± 3.95; 41.98 ± 3.79; 47.90 ± 4.83; 41.79 ± 4.25, and on the right: 46.65 ± 2.09; 39.01 ± 4.25; 47.47 ± 3.41; 38.31 ± 4.40. The mean midpoint length of the DIM was relatively higher on the left hand compared to the right hand in both females and males. In this study, variations regarding the supernumerary muscle, double interosseous space, and unipennate muscles were only observed on the right-hand side and predominantly in females, an insight that may guide in the treatment of fractures, stiffness of the hand, and compartment syndromes. [ABSTRACT FROM AUTHOR]

Individual differences in laterality and personality are expected to covary, as emotions are processed differently by the two hemispheres, and personality involves emotional behavior. Fish species are often used to investigate this topic due to the large variability in personality and laterality patterns. While some species show a positive relationship between lateralization strength and boldness, others show a negative relationship, and some show no relationship. A new way to assess the robustness of such a relationship is to manipulate both laterality and personality to examine how this affects their relationship. To this end, we conducted a fully factorial design experiment manipulating predation and group size during early development. Results showed that the strength of laterality was influenced by predation threat, while social tendency and boldness were influenced by group size. These findings suggest that early life conditions can have an impact on laterality and social behavior. The relationship between laterality and personality traits, while present, was heavily influenced by the specific trial conditions but not by the different developmental conditions. In summary, the relationship between laterality and behaviors appears to be context-dependent, yet resilient to early environmental manipulations. [ABSTRACT FROM AUTHOR]

Horses that do not only spook from novel objects but are completely unpredictable in their behavior are often referred to as “problem horses”. There are different definitions for “flight reaction”, “spooking”, and “insecurity”. A flight reaction is a physiologic response when a horse is subjected to a sudden visual or auditory stressor and tries to get away from it. “Spooking” on the other hand is a reaction to discomfort and stress without a visible or audible stressor. Insecurities are due to medical issues such as visual impairment or ataxia which decrease the horses’ ability to assess the situation. Owners often associate “spooking” behavior with visual limitations, but in most cases the eyes are not the underlying problem. To rule out ophthalmologic conditions, horses should be subjected to ocular examination, but it is often difficult to draw conclusions from findings in the eye to noticeable visual disturbances. Refractive error has an unknown effect on horses. Partial or complete hearing loss can also be a cause for spooking which can be ruled out by brainstem auditory evoked responses. Impaired hearing is a rare condition in horses and is mostly accompanying medical conditions such as temporohyoid osteoarthropathy. Horses exhibiting “spooking” habits rather suffer from stress-associated conflict behavior or laterality influencing the control over their body and their ability to cope with novel situations. Studies have shown that the visual laterality makes a difference in how visual information is processed by the horse, and which brain hemisphere is used to react to situations. Whereas the right hemisphere is used for flight and sudden reactions, the left hemisphere is predominantly used for processing information and learning. New insights have been gained regarding motor laterality, also referred to as “crookedness” in the ridden horse. Unbalanced and very crooked horses have been shown to be less able to cope with novel objects than balanced horses. A very important factor in modern horse training has been the fact that horses often refrain into learned helplessness, a state where they accept a stimulus without showing adverse reactions, as experience has shown that they can not control it. Examples are pain through the use of whips, spurs, or draw reins which are used to short-cut or accelerate the training of the horses. Therefore, to uncover the reason for the uncontrollable and dangerous actions, veterinarians should include more differential diagnoses in their problem work-up. Horses should be evaluated at rest and while being ridden using the horse grimace scale (HGS) and the ridden horse pain ethogram (RHpE) to see whether they show signs associated with discomfort, stress, and pain. The awareness for signs of laterality and learned helplessness also need to be included in the examination. Veterinarians should look for lameness, signs of discomfort, and their underlying cause such as medical conditions, rider, tack, or training methods. If no explanation for the “spooking” behavior can be determined, other reasons such as the environment (e.g., stabling conditions, feeding, turnout time and space) should be considered. By including more than just medical issues into the list of differentials and making the rider aware of other underlying causes for horses’ flight reactions, welfare in equestrian sports can be improved. [ABSTRACT FROM AUTHOR]

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The objective of this study was to investigate brain activation and functional network patterns during musical interventions in different frequency bands using functional near‐infrared spectroscopy, and to provide a basis for more effective music therapy strategy selection for patients in minimally conscious state (MCS). Twenty six MCS patients and 20 healthy people were given music intervention with low frequency (31–180 Hz), medium frequency (180–4k Hz), and high frequency (4k–22k Hz) audio. In MCS patients, low frequency music intervention induced activation of left prefrontal cortex and left primary sensory cortex (S1), also a left‐hemisphere lateralization effect of dorsolateral prefrontal cortex (DLPFC). And the functional connectivity of right DLPFC‐right S1 was significantly improved by high frequency music intervention. The low frequency and high frequency music may contribute more than medium frequency music to the recovery of consciousness. This study also validated the effectiveness of fNIRS in studies of brain function in MCS patients. [ABSTRACT FROM AUTHOR]

The serotonin-1A receptors (5-HT1A) in the two cerebral hemispheres are differentially involved in memory. The distribution of 5-HT1A receptors in the left and right amygdala is different. Furthermore, evidence shows that the 5-HT1A receptors in the left and right amygdala work differently in memory function. The basolateral amygdala (BLA) also regulates hippocampal long-term potentiation (LTP) during stress. However, which BLA structure in each hemisphere underlies such lateralized function is unclear. The present research investigated the possible involvement of 5-HT1A lateralization in the BLA on stress-induced memory impairment. 5-HT1A receptor antagonist (Way-100-635) was injected into the left, right, or bilateral BLA twenty minutes before chronic restraint stress (CRS) for 14 consecutive days. Results indicated that suppression of 5HT1A-receptors in the BLA plays an essential role in reducing the acquisition of passive avoidance in the shuttle box test and spatial memory in the Barnes maze test in the stress animals. This decrease was significant in the CRS animals with left and bilateral suppressed 5HT1A-receptors in the BLA. Field potential recording results showed that the left, right, and bilateral injection of Way-100-635 into the BLA significantly reduced the slope and amplitude of fEPSP in the CA1 area of the hippocampus in stressed rats. No significant difference was observed in neuronal arborization in the CA1 area of the hippocampus. In conclusion, the 5-HT1A receptor in the left and right sides of BLA nuclei play a different role in memory consolidation in the hippocampus under stress. [ABSTRACT FROM AUTHOR]

On the surface, the two hemispheres of vertebrate brains look almost perfectly symmetrical, but several motor, sensory, and cognitive systems show a deeply lateralized organization. Importantly, the two hemispheres are connected by various commissures, white matter tracts that cross the brain's midline and enable cross-hemispheric communication. Cross-hemispheric communication has been suggested to play an important role in the emergence of lateralized brain functions. Here, we review current advances in understanding cross-hemispheric communication that have been made using modern neuroscientific tools in rodents and other model species, such as genetic labeling, large-scale recordings of neuronal activity, spatiotemporally precise perturbation, and quantitative behavior analyses. These findings suggest that the emergence of lateralized brain functions cannot be fully explained by largely static factors such as genetic variation and differences in structural brain asymmetries. In addition, learning-dependent asymmetric interactions between the left and right hemispheres shape lateralized brain functions. Ocklenburg and Guo review the current state of knowledge on cross-hemispheric communication in the vertebrate brain, with a focus on recent research in rodents. They discuss how lateralization in sensory, memory, and motor functions can emerge from asymmetric cross-hemispheric communication. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective, cross-sectional study was conducted to analyze the implications of asymmetric baseball movements on the incidence of spondylolysis. Purpose: This study aimed to evaluate the relationship between asymmetric movements and the laterality of spondylolysis. Overview of Literature: Baseball, characterized by its asymmetric throwing and batting, may disproportionately stress one side. Lumbar spondylolysis is a frequent cause of lower back pain in young athletes, particularly those involved in activities with consistent unilateral rotations such as baseball. However, whether a link exists between the laterality in spondylolysis and the dominant throwing/batting side or whether disparities exist between pitchers and fielders remains unclear. Methods: The study included 85 players. Participants were divided into two groups: pitchers and fielders. The association between the laterality of spondylolysis and the throwing/batting side in the overall cohort and between the two groups was evaluated. Results: Among pitchers, 16 lesions appeared on the throwing side and 32 on the nonthrowing side (p=0.029). For fielders, no notable difference was observed between the two sides (p=0.363). Furthermore, batting preference did not influence the laterality of spondylolysis in either group. Conclusions: Adolescent baseball players, particularly pitchers, exhibited a higher incidence of lumbar spondylolysis on the side opposite their throwing arm. The findings of this study highlight the significant effect of asymmetrical sporting activities on the development of spondylolysis, to which pitchers are particularly susceptible. [ABSTRACT FROM AUTHOR]

In a study of patterns of language laterality in left- and right-handers, Woodhead et al. (Woodhead ZVJ, Thompson PA, Karlsson EM, Bishop DVM. 2021 R. Soc. Open Sci. 8, 200696. (doi:10.1098/rsos.200696)) noted that several tasks showed no bias to the left hemisphere in left-handed individuals. This might appear to suggest that these functions were mediated by the two hemispheres working together equally—what can be termed ‘hemispheric equipoise’. Here, I consider an alternative possibility that individuals show lateral bias on these tasks, but the bias can occur to either the left or right—a form of fluctuating asymmetry. Further analysis of the distributions of data from individuals in Woodhead et al. is compared with simulated data. The pattern of results suggests that the impression of hemispheric equipoise may be an artefact of reliance on group data: even though the group mean does not differ from zero, a high proportion of individuals are biased to the left or right.

Introduction: Chronic rhinosinusitis is inflammation of the nasal cavity and paranasal sinuses that lasts for at least twelve weeks. Paranasal sinus variations account for various pathologies, including chronic rhinosinusitis. This study assessed the anatomical variations of paranasal sinuses among patients with chronic rhinosinusitis attending otorhinolaryngology services in a tertiary hospital in Tanzania. Method: This was a descriptive prospective cross-sectional study of 120 patients aged 15 years and above who fulfilled the Rhinosinusitis Task Force criteria. A structured checklist was used to collect socio-demographic characteristics and clinical presentations. Cone-beam computed tomography scan and the Lund-Mackay scoring system were used. Data analysis was done using SPSS version 26, and p-values

The purpose of this study was to evaluate the inter-limb asymmetry in the kinematic parameters of the approach run in elite-level female Class T63/T64 long jumpers and its relationship to performance. Three Class T63 and nine Class T64 female long jumpers were examined during a competition. The temporal and kinematic parameters of their approach steps (step length: SL; step frequency: SF; average step velocity: SV) were measured using a panning video method and speed radar. The symmetry angle was the measure of inter-limb asymmetry. The results revealed that SF and SV were significantly (p < 0.05) larger in the intact lower limb. Significant (p < 0.05) asymmetry was revealed for SL, SF, and SV in 2/12, 3/12, and 1/12 jumpers, respectively. The direction of asymmetry for SF was towards the leg wearing the prosthesis for all examined jumpers. The official jump distance was significantly (p < 0.05) positively correlated with the maximum velocity attained during the approach and negatively correlated with the symmetry angle for SF. It is concluded that the observed asymmetry in SF was compensated for by the modifications observed in the SL that consequently resulted in no asymmetry in SV, leading the participants to effectively utilize their approach speed optimally in terms of long jump performance.

Background: To evaluate the association of right vs left single lung transplants (SLT) from split lung donors with long-term post-transplant recipient outcomes. Methods: We performed a retrospective review of the Scientific Registry of Transplant Recipients data of split SLT adult recipients comparing right and left lung grafts between 2005 and 2021. We used a paired donor model to account for underlying differences between donors and evaluated post-transplant patient and graft survival with Cox proportional hazard models with robust variance estimates adjusted for recipient characteristics. We also used Wilcoxon signed-rank, McNemar’s, and Bowker’s tests to evaluate complication rates between donor pairs. Results: There were 5,180 recipients with 2,590 right and left split allografts. Left SLT had higher rates of mortality (hazards ratio [HR] = 1.17, 95% confidence interval [CI]: 1.08, 1.27) and graft failure (HR = 1.16, 95% CI: 1.06, 1.26) compared to right SLT in adjusted models. There were more early deaths (5 days) (n = 319, 12.6% vs n = 270, 10.6%; p = 0.030). Conclusions: Left SLT was associated with significantly worse mortality and graft failure while right SLT was associated with more short-term complications from split lung donors. Organ listing and acceptance decisions should consider donor lung laterality.

Brain-hemisphere asymmetry/laterality is a well-conserved biological feature of normal brain development. Several lines of evidence, confirmed by the meta-analysis of different studies, support the disruption of brain laterality in mental illnesses such as schizophrenia (SCZ), bipolar disorder (BD), attention-deficit/hyperactivity disorder (ADHD), obsessive compulsive disorder (OCD), and autism. Furthermore, as abnormal brain lateralization in the planum temporale (a critical structure in auditory language processing) has been reported in patients with SCZ, it has been considered a major cause for the onset of auditory verbal hallucinations. Interestingly, the peripheral counterparts of abnormal brain laterality in mental illness, particularly in SCZ, have also been shown in several structures of the human body. For instance, the fingerprints of patients with SCZ exhibit aberrant asymmetry, and while their hair whorl rotation is random, 95% of the general population exhibit a clockwise rotation. In this work, we present a comprehensive literature review of brain laterality disturbances in mental illnesses such as SCZ, BD, ADHD, and OCD, followed by a systematic review of the epigenetic factors that may be involved in the disruption of brain lateralization in mental health disorders. We will conclude with a discussion on whether existing non-pharmacological therapies such as rTMS and ECT may be used to influence the altered functional asymmetry of the right and left hemispheres of the brain, along with their epigenetic and corresponding gene-expression patterns. [ABSTRACT FROM AUTHOR]

The notion of an increased incidence of left handers among architects and visual artists has inspired both scientific theory building and popular discussion. However, a systematic exploration of the available publications provides, at best, modest evidence for this claim. The present preregistered observational study was designed to reinvestigate the postulated association by examining hand preference of visual artists who share their artistic activities as short video clips ("reels") on the social media platform Instagram. Determining individual hand preference based on five reels for each of N = 468 artists, we identified 42 (8.97%) left handers, suggesting an incidence which is below but statistical comparable to the 10.6% expected for the general population (χ2 = 1.30; p =.25; Cohen's w = 0.05). Also, we did not find any support for the notion that the art created by left-handed artists is of higher quality than art of right handers, as no difference in public endorsement or interest were observed (reflected by the number of likes per post or account followers). Taken together, we do not find any support for difference in artistic engagement or quality between left and right handers. [ABSTRACT FROM AUTHOR]

Many functions of the human brain are organized asymmetrically and are subject to strong population biases. Some tasks, like speaking and making complex hand movements, exhibit left hemispheric dominance, whereas others, such as spatial processing and recognizing faces, favor the right hemisphere. While pattern of preference implies the existence of a stereotypical way of distributing functions between the hemispheres, an ever-increasing body of evidence indicates that not everyone follows this pattern of hemispheric functional segregation. On the contrary, the review conducted in this article shows that departures from the standard hemispheric division of labor are routinely observed and assume many distinct forms, each having a different prevalence rate. One of the key challenges in human neuroscience is to model this variability. By integrating well-established and recently emerged ideas about the mechanisms that underlie functional lateralization, the current article proposes a general mechanistic model that explains the observed distribution of segregation phenotypes and generates new testable hypotheses. [ABSTRACT FROM AUTHOR]

Objective: The goal of this study was to clarify whether clinical differences exist between patients with migraine who experience headache that is typically left‐sided ("left‐migraine") versus right‐sided ("right‐migraine") during attacks. Background: Migraine has been associated with unilateral headache for millennia and remains a supportive trait for the clinical diagnosis of migraine of the International Classification of Headache Disorders. It is currently unknown why headache in migraine is commonly unilateral, and whether headache‐sidedness is associated with other clinical features. Methods: This is a cross‐sectional study comparing left‐ versus right‐migraine using all available intake questionnaires of new patients evaluated at an academic tertiary headache center over a 20‐year period. Eligibility was based on patient written responses indicating the typical location of headache during attacks. In our analyses, the side of headache (left or right) was the predictor variable. The outcomes included various migraine characteristics and psychiatric comorbidities. Results: We identified 6527 patients with migraine, of which 340 met study eligibility criteria. Of these, 48.8% (166/340) had left migraine, and 51.2% (174/340) had right migraine. When comparing patients with left‐ versus right‐migraine, patients with left migraine experienced 3.6 fewer headache‐free days (95% confidence interval [CI] 1.3–5.9; p = 0.002) and 2.4 more severe headache days (95% CI 0.8–4.1; p = 0.004) in the previous 4 weeks. No significant differences in age, sex, handedness, migraine characteristics, or psychiatric comorbidities were identified between the two groups. Conclusions: Patients with migraine with typically left‐sided headache during attacks reported a higher burden of headache frequency and severity than those with typically right‐sided headache during attacks. These findings may have implications for our understanding of migraine pathophysiology, treatment, and clinical trial design. Plain Language Summary: In this study, we wanted to learn if patients with migraine who typically experience left‐sided headache during attacks show differences in migraine features or psychiatric comorbidities compared to patients who typically experience right‐sided headache during attacks. We reviewed the intake questionnaires of all new patients diagnosed with migraine at an academic headache center over the last 20 years. Our main finding was that patients with typically left‐sided headache reported more headache days and more severe headache days than patients with typically right‐sided headache. [ABSTRACT FROM AUTHOR]

Objective To explore the risk factors of depression and anxiety in adult patients with epilepsy and their relationship with quality of life. Methods From May 2022 to January 2023, patients diagnosed with epilepsy (aged 5 18 years) in the department of neurology of our hospital were collected. General demographic data and disease-related information were recorded. Quality of life, depression and anxiety scales were measured in all patients. SPSS26.0 software was used for multiple linear regression analysis, multiple ordered Logistic regression analysis, rank sum test, Pearson correlation analysis, etc. Results Among the 111 patients, 49.5% had depression and 43.2% had anxiety. Depression score and anxiety score were correlated with attack type, attack frequency, quality of life and right temporal lobe, and there was a significant negative correlation between life quality score and anxiety and depression score (P < 0.01). Seizure frequency, seizure type and right temporal lobe were common risk factors for depression and anxiety in patients with epilepsy (P < 0.05). Conclusion Epileptic depression and anxiety were affected by seizure frequency and seizure type, and this bad mood further affected the quality of life of patients. No clear link has been found between the lateralization of seizures and the presence of depression and anxiety states, and further research is needed. [ABSTRACT FROM AUTHOR]

Background: A comprehensive exploration evaluating left-to-right knee symmetry across all anatomical planes utilizing three-dimensional (3D) scans stands absent from the existing body of research. Therefore, the primary objectives of this investigation involved examining potential differences and resemblances in alignment and structure between left and right non-osteoarthritic (native) knees in various planes (coronal, sagittal, and axial) using three-dimensional single-photon emission computed tomography/computed tomography (SPECT/CT) images. Methods: A total of 282 native knees from 141 patients were retrospectively gathered from the hospital's records. Patients, aged between 16 and 45, who underwent Tc99m-methyl diphosphonate SPECT/CT scans for both knees, adhering to the Imperial Knee Protocol, were included. A statistical analysis was conducted, including 23 knee morphometric parameters, comparing left and right knees, and classifying them based on functional knee phenotypes across the coronal, sagittal, and axial planes. Results: Regarding the functional coronal knee phenotype, 26% of patients (n = 37) exhibited identical phenotypes in both knees (p < 0.001). Significant correlated similarities between the left and right knees were observed in the coronal plane (Pearson's r = 0.76, 0.68, 0.76, 0.76, p < 0.001) and in several morphometric measures in the sagittal plane (Pearson's r = 0.92, 0.72, 0.64, p < 0.001). Moderately correlated similarities were noted in the axial plane (Pearson's r = 0.43, 0.44, 0.43, p < 0.001). Conclusions: Only 26% of native knees exhibit an identical coronal phenotype in their contralateral knee, whereas 67% have the adjacent coronal phenotype. Strongly correlated resemblances were established across various left and right knee morphometric parameters in the coronal, sagittal, and axial planes. These findings could enhance decisions in procedures like total knee arthroplasties or osteotomies, where alignment is key to outcomes, and reveal a potential for future artificial intelligence-driven models to improve our understanding and improve personalized treatment strategies for knee osteoarthritis. [ABSTRACT FROM AUTHOR]

The activational effects of sex hormones on spatial ability have been well documented. It has been suggested that these effects might be related to hormonally induced changes in interhemispheric communication. In this EEG study, we opted to explore menstrual cycle-related changes in the efficacy of solving mental rotation tasks and laterality indices while participants were engaged with the tasks. We compared 2D and 3D mental rotation tasks, as they differ both psychometrically and in terms of lateralization. A group (n = 39) of healthy young women was tested twice, once during the mid-luteal (high estrogen and progesterone) and once during the early follicular (low levels of sex hormones) phase of menstrual cycle. The differences in power within the same frequency band on homologous sites of the left and right hemispheres were then calculated. Participants were faster, more accurate, and showed higher laterality scores when solving 3D mental rotation tasks in the early follicular phase compared to the mid-luteal phase. This indicates a higher lateralization of this specific spatial function when the levels of sex hormones are low. However, for 2D mental rotation tasks, participants showed neither shifts in efficacy nor in hemispheric laterality as a function of the menstrual cycle. This pattern of results provides further support for the notion that fluctuations in sex hormones affect laterality, and consequently, the expression of lateralized cognitive abilities. [ABSTRACT FROM AUTHOR]

Behavioural asymmetries displayed by individuals, such as hand preference and foot preference, tend to be lateralized in the same direction (left or right). This may be because their co-ordination conveys functional benefits for a variety of motor behaviours. To explore the potential functional relationship between key motor asymmetries, we examined whether footedness, handedness, or throwing arm was the strongest predictor of eyedness. Behavioural asymmetries were measured by self-report in 578 left-handed and 612 right-handed individuals. Cluster analysis of the asymmetries revealed four handedness groups: consistent right-handers, left-eyed right-handers, consistent left-handers, and inconsistent left-handers (who were left-handed but right-lateralized for footedness, throwing and eyedness). Supervised machine learning models showed the importance of footedness, in addition to handedness, in determining eyedness. In right-handers, handedness was the best predictor of eyedness, followed closely by footedness, and for left-handers it was footedness. Overall, predictors were more informative in predicting eyedness for individuals with consistent lateral preferences. Implications of the findings in relation to the origins and genetics of handedness and sports training are discussed. Findings are related to fighting theories of handedness and to bipedalism, which evolved after manual dexterity, and which may have led to some humans being right-lateralized for ballistic movements and left-lateralized for hand dexterity. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the inter-limb asymmetry in the kinematic parameters of the approach run in elite-level female Class T63/T64 long jumpers and its relationship to performance. Three Class T63 and nine Class T64 female long jumpers were examined during a competition. The temporal and kinematic parameters of their approach steps (step length: SL; step frequency: SF; average step velocity: SV) were measured using a panning video method and speed radar. The symmetry angle was the measure of inter-limb asymmetry. The results revealed that SF and SV were significantly (p < 0.05) larger in the intact lower limb. Significant (p < 0.05) asymmetry was revealed for SL, SF, and SV in 2/12, 3/12, and 1/12 jumpers, respectively. The direction of asymmetry for SF was towards the leg wearing the prosthesis for all examined jumpers. The official jump distance was significantly (p < 0.05) positively correlated with the maximum velocity attained during the approach and negatively correlated with the symmetry angle for SF. It is concluded that the observed asymmetry in SF was compensated for by the modifications observed in the SL that consequently resulted in no asymmetry in SV, leading the participants to effectively utilize their approach speed optimally in terms of long jump performance. [ABSTRACT FROM AUTHOR]